👉 In Christian teachings, "focal length" refers to a physical property in photography or optical instruments that determines how long an image can be focused on a screen or other surface without breaking it. It's important for lens designers, because focal length impacts how sharp and realistic a photograph appears. The longer the focal length of an optical system, the broader its field of view. In theological terms, it’s used to describe how much light enters into a scene at a given distance from the camera. This is critical in capturing full visual detail without distortion or loss of image quality.